All the costs of healthcare and daily eldercare make increased longevity a double-edged sword. Of course, we all want to enjoy being healthy and active for as long as possible, but there are an increasing number of years we have to fund. “Catastrophic longevity” is the risk that people will live longer and need more money than they ever imagined.

Laura Carstensen, head of the Stanford Center on Longevity, says, “Most people can’t save enough in 40 years of working to support themselves for 30 or more years of not working. Nor can society provide enough in pensions to support nonworking people that long. I’d like to see us move in a different direction toward a longer, more flexible working life.”

As you’ll read in my book, Ambition Redefined, there are many different retirement savings recommendations from reliable sources, but most experts agree you should save 10 to 20 percent of your income each year—and have a total savings of at least eight times your ending salary as of retirement. (I’ve seen recommendations as high as 11 times your salary.) Using the more conservative multiple of eight, if you and/or your partner end your working years with a total household income of $100,000, for example, you need a minimum of $800,000 in savings to cover retirement needs.

A target in the high six figures is very far away for most Americans. Even those who manage to save $1 million aren’t guaranteed that the money will last if their retirement is 30 years or more. How long your retirement savings lasts depends largely on where you live: $1 million lasts for 26 years in Mississippi, for example, and 11 years in Hawaii.

How much you need to save also depends on many factors, such as whether you’ve paid off your mortgage, the value of a home you might sell to downsize, an inheritance that might be more or less than you expect, and the status of your health. Some people who anticipate big expenses in retirement—either pleasant or unpleasant—may need to save even more.

All these numbers presume normal expenses throughout retirement—not unexpected challenges. With so many variables, it’s hard to pinpoint exactly how much you should save, and it’s a good idea to enlist the help of a financial planner. With that in mind, precise numbers are not necessary to assume you probably need to be saving more. There is not a headline that proclaims that the majority of Americans have adequate retirement savings. The US retirement savings deficit is between $6.8 and $14 trillion, which includes many people who, on the surface, don’t look like they will ever run out of money.

The savings deficit has a lot to do with the fact that the most well-intentioned savers often take costly steps backward. Those who do save—at any pace—don’t always leave their savings accounts untouched. The early tap of 401(k) plans has replaced home equity loans as the “American piggy bank.” Especially during the Great Recession, the lack of emergency savings forced millions of Americans who found themselves out of work, on the verge of losing their homes, or facing other financial emergencies to raid their retirement accounts. These accounts can’t withstand the hits: the average 401(k) savings account at a high of almost $98,000 (and, by the way, a similar average of $100,000 in the other popular savings retirement vehicle, IRAs)—is not a huge reserve. Most people do need to keep their retirement accounts intact and growing: though the wealthiest (top 1 percent) of Americans have $1 million or more stashed away in 401(k)s, even those in the top 90 percent have only $274,000 saved, and the average 80th percentile family had $116,000 saved in 2013.

Many parents who have not saved enough for their children’s college tuition also dip into retirement savings, thinking they have plenty of time to make up for early withdrawals over time. Though college tuition is a predictable expense, at a private institution it can go well beyond $175,000 for four years of room and board—per child—and just 39 percent of American families are saving in advance. This ever-increasing astronomical expense (rising an average of 3.3 percent per year at all institutions) is yet another incentive for women to always contribute to savings via flexible, lifetime work.

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